Open Tomb are Hamilton NZ based and play Slow Grinding Sludge Doom. Key members include Dane (Drums) and Sean (Gat/Vox) who have both been around forever and played in such underground bands as Gwaj, Sinfeeder, Azazel, and a bunch of others that I can't remember. Their music reminds me of the legendary Grief - Dismal Album (which I incidentally bought off of Sean's distro about 18 years ago) both in sound and in Sean's excellent vocals.
Open Tomb will soon have a split album coming out with Meth Drinker which will feature the first recording new second guitarist Kurt Silva. In the meantime you can check out their latest demo of sickness by clicking the gaping hole below.